Porcelain materials are typically made by shaping the precursor materials into a green body and firing the green body to convert it into a porcelain. The precursor materials may include alumina, clay, and a fluxing material such as feldspar or nepheline syenite. There has been much activity aimed at developing porcelain compositions which have higher strengths or are easier to prepare, for example by lowering the firing temperatures. Oda, U.S. Pat. No. 4,717,695 (1988), discloses porcelains having unglazed bending strengths greater than 1400 kg/cm.sup.2 prepared from corundum, bauxite, clay, feldspar, and optionally quartz. However, two high temperature steps, a calcining one at 900.degree.-1400.degree. C. and a firing one at 1100.degree.-1400.degree. C., are needed.